Reliability of PMN-PT Piezoelectric Material as an Actuator for High Density Hard Disk Drive

In the latest high-density hard disk drives (HDDs), the piezoelectric actuator of head gimbal assembly (HGA) is the key technology for precisely positioning the magnetic head. To increase HDD's areal density, a smaller track pitch and a faster spindle speed should be used but the faster the spindle rotates the larger the disturbance is. Hence, a newer PMN-PT piezoelectric actuator is needed to overcome the displacement bandwidth limitation restricted by the current PZT piezoelectric actuator. This paper investigated the reliability and performance of PMN-PT piezoelectric single crystal that was implemented on the a commercial HGA for the first time in an experiment. The objectives were to ensure that PMN-PT would not crack during the HDD assembly process and the performance of HDD equipped with this material was still reliable under thermal degradation. From the experiments on a prototype HGA, it was found that PMN-PT had a high degradation temperature of 150°C and was 2 times harder than PZT piezoelectric.